[foreign-memaccess+abi] RFR: 8267989: Exceptions thrown during upcalls should be handled [v4]

[Jorn Vernee]

On Wed, 2 Jun 2021 12:26:20 GMT, Jorn Vernee <jvernee at openjdk.org> wrote:

>> Hi,
>> 
>> This patch regularizes exception handling for exceptions thrown during upcalls. Exceptions thrown during upcalls are now always handled by printing out the stack trace and then calling `System::exit` (see the JBS issue for some motivation).
>> 
>> I've added some documentation for the exception handling to `CLinker::upcallStub`, as well as a new public `int` constant in `CLinker` which is the error code that is passed to `System::exit`. The returned error code can also be configured by a system property, which for now is mostly useful for testing purposes to make sure we don't get a consistent false positive.
>> 
>> Thanks,
>> Jorn
>
> Jorn Vernee has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Eagerly check whether upcall target throws any exceptions.
>   
>   Adapt the existing exception check done by MemoryHandles to be more lenient towards bound method handles which might or might not throw an exception, and re-use that check.

src/java.base/share/classes/java/lang/invoke/VarHandles.java line 649:

> 647:         }
> 648: 
> 649:         assert handle instanceof BoundMethodHandle : "Unecpexted handle type: " + handle;

Suggestion:

        assert handle instanceof BoundMethodHandle : "Unexpected handle type: " + handle;

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PR: https://git.openjdk.java.net/panama-foreign/pull/543